Last Updated: 23 November 2022

Partially Hydrolyzed Guar Gum (PHGG) For IBS – Does It Help?

Researched & Written By:
If you’ve ever tried to find a fiber supplement for IBS symptom relief, you may have come across something called partially hydrolyzed guar gum or PHGG. Or maybe you've heard of it under the brand name Sunfiber. Either way, in this guide we're going to look at what exactly it is and whether it helps with IBS. Plus, we'll even look at how much to take to support gut health.
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Table of Contents

What Is Partially Hydrolyzed Guar Gum?

To start, guar is a plant with the scientific name Cyamopsis that is part of the legume family. The ‘gum’ in guar gum comes from an inner layer (known as the endosperm) of the guar plant.1
Guar gum comes from guar plant
Guar gum comes from an inner layer (known as the endosperm) of the guar plant

Guar gum

Guar gum is typically used in small amounts as a food additive because it acts as a stabilizer, thickener, and binder. For example, guar gum can be added to cakes so that it is less crumbly when sliced or processed meats to help stabilize fat during storage.

Guar gum works well as a thickener and binder because of its high viscosity and water binding capabilities. These 2 functional properties make it a great food additive but also make it challenging to incorporate into food products in the amount necessary to use as dietary fiber. This is where the ‘partially hydrolyzed’ part comes into play.

Partially hydrolyzed guar gum

To be able to use guar gum as a dietary fiber, it has to go through a process called enzymatic hydrolysis. This involves breaking down guar gum’s carbohydrate structure into smaller carbohydrate chains.

The breakdown or ‘partial hydrolysis’ of guar gum not only changes its physical structure but also changes its’ functional properties.

So, where guar gum was highly viscous and water-binding, ‘partially hydrolyzed’ guar gum is now non-viscous and non-water binding. This makes it easy to eat in the necessary amounts to see its proposed health benefits like lowering blood sugar or cholesterol or, as we’ll talk about next, improving gut health.341

Partially hydrolyzed guar gum fiber
PHGG is a powder made from hydrolyzing the gum from the guar plant

Does PHGG Help IBS?

The American College of Gastroenterology (ACG) recommends using soluble fiber to relieve ‘global’ IBS symptoms. 5But not all soluble fibers have the same functional properties.  Meaning they can act differently in the digestive tract. 

So, where does PHGG fall into all this?

PHGG is a soluble fiber, and along with being non-viscous, it is also slowly fermenting. But does it actually help relieve IBS symptoms? Let’s check out the research.

We came across just under 10 studies examining how PHGG affects IBS symptoms. And while we’ll admit that most of the studies weren’t exactly well designed, they all indicated some symptom relief for IBS in one way or another. We’ll touch on some of the study findings below.  

Studies on PHGG for IBS

  1. For starters, the only randomized, double-blinded placebo-controlled study found that 6 g of PHGG helped improve bloating and gas in IBS patients compared to the placebo group. However, it did not improve stool frequency or abdominal pain.6
  2. One of the larger studies on PHGG looked at 188 IBS patients and showed that 5 g of PHGG improved pain and bowel habits and was better tolerated than 30 g of wheat bran.7
  3. Another study gave participants either 5 g or 10 g of PHGG per day; both groups showed an improvement in IBS symptoms, indicating that 5 g of PHGG may be the minimum dose needed to help aid in IBS symptom relief.8
  4. A few studies looked into how PHGG affects IBS-C patients, specifically.
    • For example, a small study showed that 5 g of PHGG decreased abdominal bloating in men, decreased laxative use in women, and decreased stool transit time in both genders with IBS-C.9
    • These results were replicated in another study on IBS-C patients by the same author; however, dosing information was not specified for the second study.10

Studies on PHGG for constipation

Outside of IBS, PHGG has shown to be helpful with aiding in constipation relief by different measurements like increasing the frequency of bowel movements or decreasing the use of laxatives.

A meta-analysis showed that 5-7g of PHGG was what was needed to increase bowel movement frequency. 11It seems PHGG can be pretty helpful in relieving constipation in non-IBS patients, but unfortunately, we can’t really predict how it may change bowel habits in IBS-C patients, and placebo-controlled studies are needed.

PHGG for constipation
PHGG seems especially helpful for people with IBS who have gas, bloating, and possibly constipation

PHGG may also help via microbiome & SIBO

  • More ways PHGG may be of interest to someone with IBS is how it may affect the microbiome. Some studies have shown that PHGG may increase Lactobacilli and Bifidobacteria–two types of gut bacteria associated with a healthy gut. 12One particular study showed that when patients with diarrhea were given 5 g of PHGG, they had increased Bifidobacteria along with some significant beneficial stool changes compared to the placebo group13.
  • A recent study showed that PHGG aids in the eradication of small intestinal bacterial overgrowth (SIBO) when coupled with an antibiotic. 14There seems to be considerable overlap between SIBO and IBS, so this study demonstrated a new way that PHGG may help those with IBS; however, more research is needed to support the use of PHGG for this purpose.

The takeaway from these studies

While studies on PHGG in IBS patients have measured different outcomes and shown that it provides some sort of relief for IBS in general, it seems especially helpful for people with IBS who have gas, bloating, and possibly constipation.

PHGG could also be a safe way to add fiber to the diet, especially for someone avoiding FODMAPs, as it is considered FODMAP-friendly.15

How To Take PHGG For IBS

How much to take (dosing)

Clinical trials typically use 5g/day for dosing, so that may be a good goal to work up to if you decide to try PHGG.

Of course, before starting a new supplement, talk to your doctor. And whenever increasing fiber in the diet, we suggest a slow and steady approach in addition to extra water. 

Safety & side effects

PHGG is considered safe by the FDA and few adverse effects have been reported in clinical trials.410

Summary & Verdict

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Which Foods Really Trigger Your IBS?

Discover exactly which foods you should and shouldn’t eat using our IBS Food Journal.

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  2. Deepak Mudgil, Sheweta Barak, Ami Patel, Nihir Shah. Partially hydrolyzed guar gum as a potential prebiotic source. International Journal of Biological Macromolecules, Volume 112, 2018, Pages 207-210, ISSN 0141-8130,

  3. Potential Health Benifits of Acacia Gum

  4. Rao TP, Quartarone G. Role of guar fiber in improving digestive health and function. Nutrition. 2019 Mar;59:158-169. doi: 10.1016/j.nut.2018.07.109. Epub 2018 Aug 23. PMID: 30496956.

  5. Lacy, Brian E. PhD, MD, FACG1; Pimentel, Mark MD, FACG2; Brenner, Darren M. MD, FACG3; Chey, William D. MD, FACG4; Keefer, Laurie A. PhD5; Long, Millie D. MDMPH, FACG (GRADE Methodologist)6; Moshiree, Baha MD, MSc, FACG7. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. The American Journal of Gastroenterology: January 2021 – Volume 116 – Issue 1 – p 17-44 doi: 10.14309/ajg.0000000000001036

  6. Niv, E., Halak, A., Tiommny, E. et al. Randomized clinical study: Partially hydrolyzed guar gum (PHGG) versus placebo in the treatment of patients with irritable bowel syndrome. Nutr Metab (Lond) 13, 10 (2016).

  7. Parisi GC, Zilli M, Miani MP, Carrara M, Bottona E, Verdianelli G, Battaglia G, Desideri S, Faedo A, Marzolino C, Tonon A, Ermani M, Leandro G. High-fiber diet supplementation in patients with irritable bowel syndrome (IBS): a multicenter, randomized, open trial comparison between wheat bran diet and partially hydrolyzed guar gum (PHGG). Dig Dis Sci. 2002 Aug;47(8):1697-704. doi: 10.1023/a:1016419906546. PMID: 12184518.

  8. Parisi G, Bottona E, Carrara M, Cardin F, Faedo A, Goldin D, Marino M, Pantalena M, Tafner G, Verdianelli G, Zilli M, Leandro G. Treatment effects of partially hydrolyzed guar gum on symptoms and quality of life of patients with irritable bowel syndrome. A multicenter randomized open trial. Dig Dis Sci. 2005 Jun;50(6):1107-12. doi: 10.1007/s10620-005-2713-7. PMID: 15986863.

  9. Russo, L. and Vozzella, L. and Savino, I.G. and Di Palma, S. and Sarnelli, G. and Cuomo, R. Digestive and Liver Disease. P.1.225: PARTIALLY HYDROLYZED GUAR GUM (PHGG) IN THE TREATMENT OF IRRITABLE BOWEL SYNDROME (IBS) WITH CONSTIPATION: EFFECTS OF GENDER, AGE AND BODY MASS INDEX (BMI). Supplement 3, 43, S222-S223, 2011, 10.1016/S1590-8658(11)60453-2

  10. Russo L, Andreozzi P, Zito FP, Vozzella L, Savino IG, Sarnelli G, Cuomo R. Partially hydrolyzed guar gum in the treatment of irritable bowel syndrome with constipation: effects of gender, age, and body mass index. Saudi J Gastroenterol. 2015 Mar-Apr;21(2):104-10. doi: 10.4103/1319-3767.153835. PMID: 25843197; PMCID: PMC4392570.

  11. Mahendra P. Kapoor, Masaaki Sugita, Yoshitaka Fukuzawa, Tsutomu Okubo. Impact of partially hydrolyzed guar gum (PHGG) on constipation prevention: A systematic review and meta-analysis. Journal of Functional Foods, Volume 33, 2017, Pages 52-66, ISSN 1756-4646,

  12. Edoardo G. Giannini, Carlo Mansi, Pietro Dulbecco, Vincenzo Savarino. Role of partially hydrolyzed guar gum in the treatment of irritable bowel syndrome. Nutrition,Volume 22, Issue 3, 2006, Pages 334-342, ISSN 0899-9007,

  13. Yasukawa, Zenta. A Inoue, Ryo. A Ozeki, Makoto. A Okubo, Tsutomu. A Takagi, Tomohisa. A Honda, Akira. A Naito, Yuji. Effect of Repeated Consumption of Partially Hydrolyzed Guar Gum on Fecal Characteristics and Gut Microbiota: A Randomized, Double-Blind, Placebo-Controlled, and Parallel-Group Clinical Trial. Nutrients, 072-6643, 11, 9, 2170, doi:10.3390/nu11092170

  14. Furnari, M., Parodi, A., Gemignani, L., Giannini, E.G., Marenco, S., Savarino, E., Assandri, L., Fazio, V., Bonfanti, D., Inferrera, S. and Savarino, V. (2010), Clinical trial: the combination of rifaximin with partially hydrolysed guar gum is more effective than rifaximin alone in eradicating small intestinal bacterial overgrowth. Alimentary Pharmacology & Therapeutics, 32: 1000-1006.

  15. Introducing the newly FODMAP Friendly certified Wonder Foods Partially Hydrolysed Guar Gum and PHGG PLUS!!

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